Functional color selection system

• US 5,311,212 A
• Filed: 08/04/1993
• Issued: 05/10/1994
• Est. Priority Date: 03/29/1991
• Status: Expired due to Fees

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Beretta, Giordano B.
• Primary Examiner(s): Weldon, Ulysses
• Assistant Examiner(s): Mengistu, Amare
• Application Number:
  US08/102,129
• Time in Patent Office: 279 Days
• Field of Search: 345/150, 345/154, 345/199, 358/520
• US Class Current: 345/591
• CPC Class Codes: G06F 3/04845 for image manipulation, e.g. dragging, rotation, expansion or change of colour
• CPC Class Codes: Y10S 715/961 Operator interface with visual structure or function dictated by intended use
• CPC Class Codes: Y10S 715/974 Slider control as on-screen object in operator interface

Abstract

A functional color selection system is provided for automatically generating a palette of coordinated, harmonious, and aesthetically pleasing colors from symmetrically manipulating colorimetrically specified colors in a perceptually uniform color space. The color selections system operates in a calibrated color display gamut using device independent color specifications based on internationally recognized color specification systems. A simple-to-use interface is provided for a user to select a key color on which the palette is to be based, and from the key color to select analogous and complement harmony colors. The user may also select chroma and lightness variations of the key, analogous, and complement harmony colors, and these colors will be computed at predetermined equally spaced intervals from those colors in the uniform color space. Colors are generated according to known color theories for selecting harmonious colors. The coordinated color palette selected may be saved in a palette memory for subsequent reuse in a wide variety of color presentation systems.

Claims

1. A system for producing a color palette data structure including a plurality of generated colors;

the system comprising

input means for receiving request signals from a user;

the request signals including a key color request, a color function request and a save palette request;

key color selection means, responsive to the key color request received from the user, for selecting a key color from a key color source;

the key color and each generated color being defined by a set of colorimetric coordinates defining a color location in a uniform color space;

color function selection means, responsive to the color function request received from the user for selecting a color function;

the color function defining a predetermined color relationship relating the color location of the key color in the uniform color space to the color locations of at least two generated colors in the uniform color space;

the color function computing the set of colorimetric coordinates of the at least two generated colors using the set of colorimetric coordinates of the key color;

color generation means, responsive to the color function selection means, for generating the set of colorimetric coordinates for the at least two generated colors using the set of colorimetric coordinates of the key color according to the predetermined color relationship defined by the selected color function, and for storing in the color palette data structure the set of colorimetric coordinates for of the at least two generated colors;

display means, cooperatively associated with and responsive to the key color selection means and to the color generation means, and including a display device having a display screen, for converting the set of colorimetric coordinates of the key color and of each generated color stored in the color palette data structure to color output signals representing colors producible on the display device;

the display means further displaying concurrently on the display screen the key color and each of the generated colors stored in the color palette data structure using the color output signals; and

memory means for storing the color palette data structure in response to the save palette request received from the user.

2. The system of claim 1 wherein

the request signals further include a color delete request;

and

the system further includes coordinated color deletion means, responsive to the color delete request received from the user, for deleting one of the generated colors from the color palette data structure.

3. The system of claim 1 wherein the set of colorimetric coordinates are cylindrical coordinates and include a hue-angle coordinate, a chroma coordinate, and a lightness coordinate.

4. The system of claim 3 wherein the color function is an analogous harmony color function relating the key color to first and second analogous harmony colors;

the analogous harmony color function generating the set of colorimetric coordinates of the first analogous harmony color by incrementing the hue-angle coordinate of the key color in the uniform color space by a first angle value between 15 and 30 degrees;

the analogous harmony color function further generating the set of colorimetric coordinates of the second analogous harmony color by decrementing the hue-angle coordinate of the key color in the uniform color space by the first angle value.

5. The system of claim 4 wherein the analogous harmony color function further relates the key color to third and fourth analogous harmony colors;

the analogous harmony color function further generating the set of colorimetric coordinates of the third analogous harmony color by incrementing the hue-angle coordinate of the key color in the uniform color space by a third angle value equal to twice the first angle value;

the analogous harmony color function further generating the set of colorimetric coordinates of the fourth analogous harmony color by decrementing the hue-angle coordinate of the key color in the uniform color space by a fourth angle value equal to twice the first angle value.

6. The system of claim 3 wherein the color function is a complement color function relating the key color to first and second complemented colors;

the complement color function generating the set of colorimetric coordinates of the first complement color by incrementing the hue-angle coordinate of the key color in the uniform color space by 120 degrees;

the complement color function further generating the set of colorimetric coordinates of the second complement color by decrementing the hue-angle coordinate of the key color in the uniform color space by 120 degrees.

7. The system of claim 3 wherein the color function is a chroma variation color function relating the key color to at least two chroma variation colors;

the chroma variation color function generating the set of colorimetric coordinates of a first chroma variation color by incrementing the chroma coordinate of the key color in the uniform color space by a chroma change quantity determined using a line segment passing through the key color and an achromatic axis in the uniform color space;

the chroma variation color function further generating the set of colorimetric coordinates of a second chroma variation color by decrementing the chroma coordinate of the key color by the chroma change quantity.

8. The system of claim 3 wherein the color function is a lightness variation color function relating the key color to at least two lightness variation colors;

the lightness variation color function generating the set of colorimetric coordinates of a first lightness variation color by incrementing the lightness coordinate of the key color in the uniform color space by a lightness change quantity defined by creating an interval scale in the uniform color space;

an end of the interval scale being determined from the lightness coordinate of the key color;

the lightness variation color function further generating the set of colorimetric coordinates of a second lightness variation color by decrementing the lightness coordinate of the key color by the lightness change quantity.

9. A system for producing a color palette data structure including a plurality of generated colors;

the system comprising

input means for receiving request signals from a user;

the request signals including a key color request, a color function request and a save palette request;

key color selection means, responsive to the key color request received from the user, for selecting a key color from a key color source;

the key color and each of the plurality of generated colors being defined by a set of cylindrical colorimetric coordinates in a uniform color space, the set of cylindrical colorimetric coordinates including a hue-angle coordinate, a lightness coordinate, and a chroma coordinate;

color function selection means, responsive to the color function request received from the user, for selecting a color function from a plurality of color functions;

each color function producing at least one of the plurality of generated colors;

the plurality of color functions including,

an analogous harmony color function relating the key color to an analogous harmony color;

the analogous harmony color function producing the set of cylindrical colorimetric coordinates of the analogous harmony color by varying the hue-angle coordinate of the key color in the uniform color space by a first angle value; and

a complement color function relating the key color to a complement color;

the complement color function producing the set of cylindrical colorimetric coordinates of the complement color by varying the hue-angle coordinate of the key color in the uniform color space by a third angle value;

color generation means, responsive to the color function selection means, for generating the set of cylindrical colorimetric coordinates for the at least one generated color using the set of cylindrical colorimetric coordinates for the key color according to the selected color function, and for storing the set of cylindrical colorimetric coordinates for the at least one generated color in the color palette data structure;

display means, cooperatively associated with and responsive to the key color selection means and the color generation means, and including a display device having a display screen, for converting the set of cylindrical colorimetric coordinates of the key color and of each generated color stored in the color palette data structure to color output signals representing colors producible on the display device;

the display means further displaying concurrently on the display screen the key color and each generated color stored in the color palette data structure; and

memory means for storing the color palette data structure in response to the save palette request received from the user.

10. The system of claim 9

wherein the request signals received from the user further include a user selected color request indicating a user selected color selected by the user from the key color, the analogous harmony color and the complement color;

and

wherein the plurality of color functions further includes

a lightness variation color function relating the user selected color to at least one lightness variation color;

the lightness variation color function producing the set of cylindrical colorimetric coordinates of the at least one lightness variation color by incrementing the lightness coordinate of the user selected color by a lightness change quantity defined by creating an interval scale in the uniform color space;

an end of the interval scale being determined from the lightness coordinate of the user selected color; and

a chroma variation color function relating the user selected color to at least one chroma variation color;

the chroma variation color function producing the set of cylindrical colorimetric coordinates of the at least one chroma variation color by incrementing the chroma coordinate of the user selected color by a chroma change quantity determined using a line segment passing through the user selected color and an achromatic axis in the uniform color space.

11. The system of claim 10 wherein

the plurality of color functions further includes a shift hue function relating the key color to a modified key color;

the shift hue function producing the set of cylindrical colorimetric coordinates of the modified key color by incrementing the hue-angle coordinate of the key color in the uniform color space by a shifted hue angle to produce a modified hue-angle coordinate;

the shifted hue angle having an angle value less than the first angles value; and

when the color function selection is the shift hue function, the color generation means produces the set of cylindrical colorimetric coordinates, including the modified hue-angle coordinate, of the modified key color, and stores the modified key color in the color palette data structure.

12. The system of claim 11 wherein, when the color function selection is the shift hue function, the color generation means further produces, for each generated color generated using a prior selected color function, the set of colorimetric coordinates of a respective modified generated color according to the prior selected color function thereof, using the modified hue-angle coordinate of the modified key color;

the color generation means further storing the modified generated colors in the color palette data structure.

13. The system of claim 9

wherein the first angle value is between 15 and 30 degrees;

and

wherein the analogous harmony color function further relates the key color to a second analogous harmony color;

the analogous harmony color function further producing the set of cylindrical colorimetric coordinates of the second analogous harmony color by varying the hue-angle coordinate of the key color in the uniform color space by a second angle value equal to twice the first angle value.

14. The system of claim 9 wherein the third angle value is 180 degrees.

15. The system of claim 9 wherein the plurality of color functions further includes a second complement color function relating the key color to first and second complement colors;

the second complement color function producing the set of cylindrical colorimetric coordinates of the first complement color by incrementing the hue-angle coordinate of the key color in the uniform color space by 120 degrees;

the second complement color function further producing the set of cylindrical colorimetric coordinates of the second complement color by decrementing the hue-angle coordinate of the key color in the uniform color space by 120 degrees.

16. The system of claim 9 wherein the plurality of color functions further includes a shift hue function relating the key color to a modified key color;

the shift hue function producing the set of cylindrical colorimetric coordinates of the modified key color by varying the hue-angle coordinate of the key color in the uniform color space by a shifted hue angle value to produce a modified hue-angle coordinate;

the shifted hue angle value being less than the first angle value.

17. The system of claim 16 wherein the shifted hue angle has an angle value equal to one half of the first angle value.

18. The system of claim 9 further including color deletion means for deleting one of the generated colors from the color palette data structure;

the color deletion means being responsive to a color delete request received from the user.

19. A method of operating a machine to produce a color palette data structure including a plurality of generated colors;

the machine including a user input device for providing signals indicating requests from a machine user, a processor, a display, and a memory;

the method comprising the steps of

receiving a first user request signal from the user input device indicating a selection of a key color by the machine user from a key color source;

the key color and each generated color being defined by a set of colorimetric coordinates defining a color location in a uniform color space;

displaying the key color on the display in response to the selection of the key color;

the step of displaying the key color including converting the set of colorimetric coordinates defining the key color to color output signals representing a color reproducible on the display;

storing the set of colorimetric coordinates of the key color in the color palette data structure;

receiving a second user request signal from the user input device indicating a selection of a color function by the machine user;

the color function defining a predetermined color relationship relating the color location of the key color in the uniform color space to color locations of at least two generated colors in the uniform color space;

the color function computing the set of colorimetric coordinates of the at least two generated colors using the set of colorimetric coordinates for the key color;

in response to the second user request signal indicating the selection of the color function,

generating the set of colorimetric coordinates for at least two generated colors using the set of colorimetric coordinates for the key color according to the predetermined color relationship defined by the color function selected;

storing the set of colorimetric coordinates of each generated color in the color palette data structure;

converting the set of colorimetric coordinates for each generated color into color output signals representing a color producible on the display, and

displaying the key color and each generated color stored in the color palette data structure concurrently on the display; and

storing the color palette data structure in the memory of the machine.

20. The method of claim 19,

wherein the set of colorimetric coordinates in the uniform color space include a cylindrical hue-angle coordinate;

and

wherein the color function selected by the machine user is selected from a plurality of color functions including,

an analogous harmony color function relating the key color to first and second analogous harmony colors;

the analogous harmony color function producing the set of colorimetric coordinates of the first analogous harmony color by incrementing the hue-angle coordinate of the key color in the uniform color space by a first angle value;

the analogous harmony color function further producing the set of colorimetric coordinates of the second analogous harmony color by decrementing the hue-angle coordinate of the key color in the uniform color space by the first angle value; and

a complement color function for relating the key color to first and second complement colors;

the complement color function producing the set of colorimetric coordinates of the first complement color by incrementing the hue-angle coordinate of the key color in the uniform color space by a second angle value;

the complement color function further producing the set of colorimetric coordinates of the second complement color by decrementing the hue-angle coordinate of the key color in the uniform color space by the second angle value.

21. The method of claim 20 further including

receiving a third user request signal from the user input device indicating a selection by the machine user of a displayed color from the key color, the analogous harmony color and the complement color;

and

receiving a fourth user request signal from the user input device indicating a selection by the machine user of a second color function;

and wherein

the step of generating the set of colorimetric coordinates for the generated color is further responsive to the selection of the second color function;

the set of colorimetric coordinates in the uniform color space further include a chroma coordinate and a lightness coordinate; and

the plurality of color functions further includes

a lightness variation color function relating the displayed color to at least two lightness variation colors;

the lightness variation color function producing the set of colorimetric coordinates of a first lightness variation color by incrementing the lightness coordinate of the displayed color by a lightness change quantity defined by creating an interval scale in the uniform color space;

an end of the interval scale being determined from the lightness coordinate of the displayed color;

the lightness variation color function further producing the set of colorimetric coordinates of a second lightness variation color by decrementing the lightness coordinate of the displayed color by the lightness change quantity; and

a chroma variation color function relating the displayed color to at least two chroma variation colors;

the chroma variation color function producing the set of colorimetric coordinates of a first chroma variation color by incrementing the chroma coordinate of the displayed color by a chroma change quantity determined using a line segment passing through the displayed selection color and an achromatic axis in the uniform color space;

the chroma variation color function further producing the set of colorimetric coordinates of a second chroma variation color by decrementing the chroma coordinate of the displayed color by the chroma change quantity.

22. The method of claim 21 wherein

the color function indicated by the selection of the second color function further includes a shift hue function relating the key color to a modified key color;

the shift hue function producing the set of colorimetric coordinates of the modified key color by varying the hue-angle coordinate of the key color in the uniform color space by a shifted hue angle value to produce a modified hue-angle coordinate;

the shifted hue angle value being less than the first angle value;

when the color function indicated by the selection of the second color function is the shift hue function, the steps of generating the set of colorimetric coordinates for the generated color further includes

generating the set of colorimetric coordinates of the modified key color, including the modified hue-angle coordinate, according to the shift hue function; and

for each generated color generated from the color function selected by a prior selection of a color function, generating the set of colorimetric coordinates of a respective modified generated color according to the color function selected by the prior selection using the modified hue-angle coordinate of the modified key color; and

the step of storing the generated color and the key color in the color palette data structure includes storing each modified generated color and the modified key color in the color palette data structure.

23. The method of claim 20 wherein the first angle value is between 15 and 30 degrees.

24. The method of claim 23 wherein the shifted hue angle value is one half of the first angle value.

25. The method of claim 20 wherein the second angle value is 120 degrees.

26. The method of claim 19 further including

receiving a third request signal from the user input device indicating a color deletion request by the machine user;

the color deletion request including signals indicating a selected generated color selected from the plurality of generated colors displayed on the display;

deleting the selected generated color from the display and from the color palette data structure in response to the color deletion request.

27. A method of operating a machine to produce a color palette data structure including a plurality of generated colors;

the machine including a user input device for providing signals indicating requests from a machine user, a processor, a display, and a memory;

the method comprising the steps of

colorimetrically measuring a plurality of colors producible by the display to produce a measured color gamut for the display, and storing the measured color gamut in the memory;

receiving a first user request signal from the user input device indicating a selection by the machine user of a key color from a key color source;

the key color, each generated color and the plurality of colors in the measured color gamut being defined by a set of colorimetric coordinates defining a color location in a uniform color space;

the set of colorimetric coordinates for each color including a hue-angle coordinate, a chroma coordinate, and a lightness coordinate;

in response to the selection of the key color, converting the set of colorimetric coordinates defining the key color to color output signals representing a color in the measured color gamut of the display and displaying the key color on the display;

storing the set of colorimetric coordinates of the key color in the color palette data structure;

receiving a second user request signal from the user input device indicating a selection of a color function by the machine user selected from a plurality of color functions including

an analogous harmony color function relating the key color to first and second analogous harmony colors;

the analogous harmony color function producing the set of colorimetric coordinates of the first analogous harmony color by incrementing the hue-angle coordinate of the key color in the uniform color space by a first angle value;

the analogous harmony color function producing the set of colorimetric coordinates of the second analogous harmony color by decrementing the hue-angle coordinate of the key color in the uniform color space by the first angle value;

a direct complement color function relating the key color to a direct complement color;

the direct complement color function producing the set of colorimetric coordinates of the direct complement color by varying the hue-angle coordinate of the key color in the uniform color space by a second angle value;

a lightness variation color function relating an input color to at least one lightness variation color;

the lightness variation color function producing the set of colorimetric coordinates of the at least one lightness variation color by varying the lightness coordinate of the input color by a lightness change quantity defined by creating an interval scale in the uniform color space;

one end of the interval scale being determined from the lightness coordinate of the input color;

the other end of the interval scale being at an edge of the measured color gamut;

wherein the second user request signal further indicates the input color;

the input color being selected from the key color, the first and second analogous harmony colors, and the direct complement color; and

a chroma variation color function relating the input color to at least one chroma variation color;

the chroma variation color function producing the set of colorimetric coordinates of the at least one chroma variation color by varying the chroma coordinate of the input color by a chroma change quantity determined using a line segment passing through the input color and an achromatic axis in the uniform color space, and extending to an edge of the measured color gamut;

in response to the selection of the color function, generating the set of colorimetric coordinates for at least one generated color according to the color function;

storing the set of colorimetric coordinates of each generated color in the color palette data structure;

converting the set of colorimetric coordinates for each generated color stored in the color palette data structure into respective color output signals representing a displayable generated color in the measured color gamut of the display, and displaying the displayable generated color using the respective color output signals concurrently with the key color on the display;

receiving a third request signal indicating a save palette request by the machine user; and

storing the color palette data structure in the memory of the machine in response to the save palette request.

28. The method of claim 27 further including

receiving a fourth user request signal from the user input device indicating a generated color deletion request by the machine user;

the generated color deletion request including a selected generated color selected from the plurality of generated colors displayed on the display;

deleting the selected generated color from the display and from the color palette data structure in response to the generated color deletion request.

29. The method of claim 27 wherein the analogous harmony color function further relates the key color to third and fourth analogous harmony colors;

the analogous harmony color function producing the set of colorimetric coordinates of the third analogous harmony color by incrementing the hue-angle coordinate of the key color in the uniform color space by a second angle value equal to twice the first angle value;

the analogous harmony color function further producing the set of colorimetric coordinates of the fourth analogous harmony color by decrementing the hue-angle coordinate of the key color in the uniform color space by the second angle value.

30. The method of claim 29 wherein the plurality of color functions further includes a triadic complement color function relating the key color to first and second triadic complement colors;

the triadic complement color function producing the set of colorimetric coordinates of the first triadic complement color by incrementing the hue-angle coordinate of the key color in the uniform color space by 120 degrees;

the triadic complement color function further producing the set of colorimetric coordinates of the second triadic complement color by decrementing the hue-angle coordinate of the key color in the uniform color space by 120 degrees.

31. The method of claim 30 wherein

the plurality of color functions further includes a shift hue function the key color to a modified key color;

the shift hue producing the set of colorimetric coordinates of the key color by varying the hue-angle coordinate of the key the uniform color space by a shifted hue angle value to a modified hue-angle coordinate; and

when the color function selected by the machine user is the function, the step of generating the set of color coordinates for the generated color in response to the of the color function includes

generating the set of colorimetric coordinates of the key color according to the shift hue function; and

selection

for each generated color generated from a prior selection color function, generating the set of color coordinates of a respective modified generated according to the color function selected by selection using the modified hue-angle coordinate modified key color; and

the step of storing the generated color in the color palette data includes storing the modified key color and each generated color therein.